1. Field of the Invention
This invention relates to a method of producing relatively rapidly soluble composite materials which are formed from materials of relatively low solubility and which possess increased machine handleability properties over the starting relatively low solubility material. The method is useful in producing rapidly soluble composites from a wide variety of starting materials. More particularly, the method is particularly suitable for producing rapidly soluble, machine handleable composites of materials which are of clinical importance, such as chelating agents. The method is particularly important in the clinical field since the rapidity with which chelating agents go into solution can determine their relative effectiveness in each application. Many commercially available organic compounds, particularly many chelation agents, are generally not rapidly soluble in solutions, in particular aqueous solutions, and are not readily processed, packaged, and handled by machine. The present invention was developed to overcome these problems.
2. Description of the Prior Art
Most of the known prior art relating generally to rapidly soluble compounds and to chelation compounds involves the synthesis of EDTA, its salts and derivatives, and also to methods of increasing the solubility of various pharmaceuticals. For example, U.S. Pat. No. 2,558,923 discloses a method for treating an aqueous solution which contains a sodium salt of EDTA (ethylenediaminetetraacetic acid) for the purpose of recovering the EDTA from the reaction mixture. The disclosure is primarily directed towards the synthesis and recovery of the diacid for the purpose of using it as an intermediate reaction product in the synthesis of other amino compounds.
Similarly, U.S. Pat. No. 2,845,457 discloses a method of manufacture of EDTA derivatives by using a single-stream, acid-stabilized, equimolar mixture of hydrogen cyanide and formaldehyde, with the reagents being added simultaneously. The method is directed towards the single-step production of EDTA derivatives.
U.S. Pat. No. 2,859,104 discloses a method of using an EDTA derivative, namely, N,N-dihydroxyethyl N',N' dicarboxymethyl ethylenediamine and its salts as an agent to collect, hold, and provide a source of trace metals in plants. The complex of the diamine and a metal is poured near, sprayed on or mixed with the soil of an agricultural product deficient in the metal of interest.
U.S. Pat. Nos. 3,393,233 and 3,449,414 show, respectively, methods for isolating EDTA from copper containing solutions and for the rapid synthesis of EDTA and derivatives by the use of a cascade-reactor system.
U.S. Pat. No. 3,607,931 discloses a method of producing a rapidly dissolving EDTA salt, i.e. the disodium salt wherein a mixed solution of EDTA partial salts is adjusted to a given temperature and a precise pH, to precipitate a very pure, rapidly soluble disodium EDTA. This method involves a somewhat involved procedure and requires a number of reagents for the completion of the reaction.
U.S. Pat. No. 4,036,990 discloses a method to increase the rate of solubility of materials by mixing the materials with a beta-1, 4 glucan, then pulverizing the mixture. This method requires the introduction of a second substance, i.e. the glucan, into the system in which the compound of interest is dissolved. This is undesirable in many areas of clinical and medicinal chemistry.